Wireless communications technologies such as cellular telephone networks and Wireless Local Area Networks (“WLANs”) currently enjoy increasing popularity in terms of growing number of subscribers and the extension of technological capabilities in order to support new services. Increases in the overall number of users combined with increased bandwidth usage per user as a result of introduction of new services can result in a shortage of bandwidth. In response to bandwidth shortage regulatory authorities may reallocate regulated spectrum. For example, bandwidth may be taken from a technology in decline or of lesser importance and allocated to a technology that is growing in popularity or of greater importance. In the case of a currently proposed reallocation in Japan which is illustrated in FIG. 1, the reason for reallocating bandwidth may be to more closely follow allocations made by other nations which form a de facto international standard. Whatever the reason for bandwidth reallocation, the transition between allocation models can be problematic.
One problem associated with reallocation of spectrum is migration of equipment. Simultaneous use of equipment that conforms with the new allocation and equipment that conforms with the legacy allocation can result in interference and incompatibility issues. In the example illustrated in FIG. 1 the channel centers are being reassigned in a portion of the spectrum, and new channels are being added by expanding the boundaries of the spectrum. It will be apparent that operation on channels 34, 38, 42 and 46 of the existing allocation will interfere with channels 36, 40, 44 and 48 of the target spectrum. In particular, existing channel 34 will interfere with target channel 36, existing channel 38 will interfere with target channels 36 and 40, existing channel 42 will interfere with target channels 40 and 44, and so on. However, regulators often allow a period of time for the old equipment to continue operation under the old regulatory rules. This time period overlaps the time for new equipment to be deployed under the guidelines of the new regulatory rules. During this time overlap, significant operational problems may be encountered. For example, equipment may be deployed following either the old rules or the new rules. This tends to exacerbate the incapability and system cost problems. At some point in time the old equipment becomes prohibited and the new equipment rules must be followed. While it might be possible to replace the legacy equipment with new equipment at a specified point in time, this could impose a significant burden on network operators in terms of effort to remove and install equipment and the cost of the new equipment. It is therefore desirable to have technology to gracefully migrate between the two spectrum allocations.